Providing cryotherapy with a balloon catheter having a non-uniform thermal profile

Abstract

A cryotherapy catheter can include an elongate member and an inflatable balloon portion at a distal end of the elongate member. The inflatable balloon portion can have an external surface and an interior chamber, and the external surface can include a cooling region and a thermally insulated region. The interior chamber can be configured to receive during a cryotherapy procedure a cryogenic agent for extracting heat from body tissue that is in contact with the cooling region. A thermal profiling component can be disposed in the interior chamber and configured to thermally insulate the thermally insulated region from the cryogenic agent to minimize heat extraction by the cryogenic agent from body tissue that is in contact with the thermally insulated region.

What is claimed is: 
     
       1. A cryotherapy catheter comprising:
 an elongate member and an inflatable balloon portion at a distal end of the elongate member, the inflatable balloon portion having an external surface and an interior chamber and comprising an inner balloon and an outer balloon; the external surface comprising a cooling region and a thermally insulated region; the interior chamber configured to receive during a cryotherapy procedure a cryogenic agent for extracting heat from body tissue that is in contact with the cooling region; and 
 an insulative material disposed between the inner balloon and the outer balloon, or adjacent to a surface of at least one of the inner balloon or the outer balloon; the insulative material comprising a material having at least one of a plurality of air pockets formed therein or a plurality of hollow beads disposed therein; 
 wherein the insulative material is disposed in a manner that thermally insulates the thermally insulated region from the cryogenic agent to minimize heat extraction by the cryogenic agent from body tissue that is in contact with the thermally insulated region. 
 
     
     
       2. The cryotherapy catheter of  claim 1 , wherein inner insulative material is disposed adjacent to a surface of the inner balloon, and an air gap is disposed between the inner insulative material and the surface of the inner balloon. 
     
     
       3. The cryotherapy catheter of  claim 1 , wherein the insulative material is disposed in multiple non-overlapping layers and configured to provide multiple gradations of thermal insulation. 
     
     
       4. The cryotherapy catheter of  claim 1 , wherein the insulative material is configured to form the cooling region in a treatment pattern shape which, during the cryotherapy procedure, causes body tissue that is adjacent to the treatment pattern shape to be cryoablated, without cryoablating body tissue that is not in contact with the treatment pattern shape. 
     
     
       5. The cryotherapy catheter of  claim 4 , wherein the treatment pattern shape is configured to correspond to at least a part of a Maze-Cox pattern. 
     
     
       6. The cryotherapy catheter of  claim 4 , wherein the treatment pattern shape is configured to thermally insulate bodily tissue or fluids that are in contact with a proximal end of the inflatable balloon portion during the cryotherapy procedure from a cooling effect of the cryogenic agent.